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In this study, we compared the transient self-heating behavior of a homoepitaxial β-Ga2O3 MOSFET and a GaN-on-Si HEMT using nanoparticle-assisted Raman thermometry and thermoreflectance thermal imaging. The effectiveness of bottom-side and double-side cooling schemes using a polycrystalline diamond substrate and a diamond passivation layer were studied via transient thermal modeling. Because of the low thermal diffusivity of β-Ga2O3, the use of a β-Ga2O3 composite substrate (bottom-side cooling) must be augmented by a diamond passivation layer (top-side cooling) to effectively cool the device active region under both steady-state and transient operating conditions. Without no proper cooling applied, the steady-state device-to-package thermal resistance of a homoepitaxial β-Ga2O3 MOSFET is 2.6 times higher than that for a GaN-on-Si HEMT. Replacing the substrate with polycrystalline diamond (under a 6.5 μm-thick β-Ga2O3 layer) could reduce the steady-state temperature rise by 65% compared to that for a homoepitaxial β-Ga2O3 MOSFET. However, for high frequency power switching applications beyond the ~102 kHz range, bottom-side cooling (integration with a high thermal conductivity substrate) does not improve the transient thermal response of the device. Adding a diamond passivation over layer diamond not only suppresses the steadystate temperature rise, but also drastically reduces the transient temperature rise under high frequency operating conditions.
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2023 IEEE Energy Conversion Congress and Exposition (ECCE)
This paper presents an improved on-state resistance (RDSon) measurement scheme for high and low-side GaN FETs, which is critical for reliable and precise assessment of GaN HEMT power devices’ lifetime and degradation patterns. The proposed circuit is based on an active voltage clamp using Si MOSFET and Schottky and Zener diodes. The proposed circuit features lower parasitic inductances and capacitances by replacing the Si MOSFET with e-mode GaN FET. This modification contributed to much lower ringing and spikes in the voltage and current waveform of both the measurement FET and the DUT. The absence of an embedded body diode in the GaN device in the measurement circuit allows zero reverse recovery operation, making it more viable in high-frequency power converters. This study also provides a detailed design analysis of a bootstrap GaN-based on-state voltage (VDSon) sensing scheme for high-side FETs, useful in multiple converter configurations for in-situ devices’ health monitoring and conditioning. Simulation and experimental results validate the performance and features of the proposed concepts.
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- Award ID(s):
- 2239966
- PAR ID:
- 10577638
- Publisher / Repository:
- IEEE
- Date Published:
- ISBN:
- 979-8-3503-1644-5
- Format(s):
- Medium: X
- Location:
- Nashville, TN, USA
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Proceeding:
- https://doi.org/10.1109/ECCE53617.2023
